106 THE MEDUSAE. 



eighty), about the same bell outline and conformation of gonads, and essen- 

 tially similar coloration. Browne states that in G. hornelU the tentacles are 

 arranged in sixteen groups ; but from an examination of his figure (: OS*", 

 pi. 1, fig. 6) it appears that this grouping indicates the location of the 

 sixteen otocysts, and is in no way comparable to such a grouping of tenta- 

 cles as is seen in Gossea (p. 103). In my description of G. pelagicus (: 04, 

 p. 256) I considered the small size of the sucking discs of this species suffi- 

 cient to separate it specifically from G. suvaensis ; but a second examination of 

 the specimen has shown that this supposed character is variable in different 

 tentacles, and perhaps due largely to preservation, so that I was not justified 

 in making a new species for this form, which is really G. suvaensis. 



In the second group, characterized by the form of the gonads and by 

 having a large and variable number of otocysts, it appears that several good 

 species can be distinguished. The number of otocysts, even though variable, 

 is apparently of specific significance, for while G. vertens and G. murbachii have 

 about as many otocysts as tentacles or slightly fewer, G. depressum and the 

 specimens described by Kirkpatrick (: 03) under the name G. acjassizii have 

 nearly or quite twice as many, and this difference is apparently constant, for 

 very considerable series of G. vertens cind G. imtrbachiihcive now been examined by 

 various observers ; the latter, owing to its common use as laboratory material 

 and as subject for experiment, being very well known indeed. The differences 

 between G.vertetis and G.mm-bachii are slight, consisting of a slightly higher 

 bell in the former and stouter tentacles in the latter ; but they appear to be 

 constant, and must therefore be recognized in the nomenclature of the genus. 



Gonionenius depressum Goto, and the specimens described by Kirkpatrick 

 (: 03) as G. arj assizii MxivhsLch. and Shearer, both from Japan, are undoubtedly 

 identical, agreeing as they do in the form of the gonads, number and form of the 

 tentacles, and number of otocysts ; but it is doubtful whether Kirkpatrick's 

 identification of his specimens with Murbach and Shearer's (: 03) species is 

 correct ; for, while the latter authors state that G. agassizii has rather fewer 

 otocysts than tentacles (though without giving actual figures), Kirkpatrick 

 (: 03) finds the otocysts almost twice as numerous as the tentacles. For 

 this reason I prefer, at least for the present, to retain both G. depressum and 

 G. agassizii as distinct species, classing Kirkpatrick's specimens as G. depressum. 

 The distinction between G. agassizii and G. vertens, the greater number of ten- 

 tacles of the former, must be tested in a larger series before a final decision 

 can be reached. 



